This invention relates to a tank valve. Tank valves are responsive to water levels in a tank. The water is released from the tank to the toilet bowl by opening a flush valve. The tank valve opens to resupply the tank after the water level falls below some predetermined level, and continues to be open to flow until the water level is restored. During this cycle, the flush valve will have closed to enable the tank to be refilled.
The bowl itself has a siphon construction, and empties when sufficient water has been dumped from the tank to raise the level of water in the bowl high enough to start the siphoning action. Discharge from the bowl continues until the siphoning action by having drawn the level below a lid which otherwise excludes air from the siphon send. The discharge includes water that continues to arrive from the tank for a time after the siphoning begins, but finally a lower level is reached and the siphoning stops. The bowl will then have been emptied. Now it is necessary to supply the bowl with enough water to make a gas seal, and receive the next load, but not enough to restart the siphoning. This additional water is supplied through a separate line, called a fill line, which discharges through the tank overflow pipe into the bowl. While the refill line flows at all times when the tank valve is open to flow, the bowl refill operation basically takes place after the flush valve has closed and the tank is also being refilled. Because relatively little water is needed for the bowl, compared to the amount needed to refill the tank, the refill line generally delivers only a trickle.
The above system works well when there is a tank with a substantial reserve volume and a substantial pressure head. However, there is a class of toilet called the "low-boy" in which only a small tank is provided, and it is not much higher than the bowl itself. This tank is unobtrusive in the bathroom, and is favored by many designers. The older system does not provide a tank with a sufficient quantity of water per flush, nor a sufficient water pressure to make an effective flush in such an environment. For this reason, a variation on this system has been developed in which a much larger proportion of the water for the flush is supplied from the tank valve during the flushing operation. The tank valve then provides water for storage, water under pressure to assist in the flush, and water to refill the bowl. During the time the tank is discharging, the tank valve is also discharging to the bowl rather primarily only than to the tank. This provides for an effective rinse of the bowl wall, and for a major supplement to the water for the discharge of the bowl.
An additional further function required of the tank valve for this purpose is that during the tank discharge, a substantial portion of the tank valve flow is diverted to the bowl, instead of primarily only to the tank to refill the tank.
The manufacture of tank valves is highly competitive. It is a large volume operation, and lower costs translate very quickly into better sales. Still, these valves must be among the most trustworthy items in the home or office building, because their failure can lead to considerable and very expensive water damage. Thus, economy cannot be purchased by lessening the quality or reliability of the valve. The efforts must be toward innovative valves which are inherently less expensive to make, and which are equally reliable and functional, or more so. This invention is such a product.
Prior tank valves capable of providing the described secondary diversion function have tended toward the use of secondary float responsive valves which have been an additional substantial cost or have been more complicated than need be, or they have discharged constantly through both paths. It is an object of this invention to provide a two-function tank valve that can provide the desired diversion while utilizing basic tank valve elements whose economy of manufacturing and reliability are already well-established, and with the use of elegantly simple and inexpensive additional structure. An example of a prior arrangement is shown in Antunez U.S. Pat. No. 4,420,845, issued Dec. 20, 1983.